Centrifugal pump

Abstract

The centrifugal pump comprises a pump body, a pump shaft, a sealing mechanism, an impeller and an axial magnetic flux motor. The pump shaft is rotatably installed on the pump body through a sealing mechanism, and a sealing cavity is formed in the pump body. The impeller is installed on the pump shaft and located in the sealing cavity, at least one end of the pump shaft is provided with an axial magnetic flux motor, the axial magnetic flux motor drives the impeller to rotate through the pump shaft, and conveying of fluid is achieved. According to the centrifugal pump, the axial magnetic flux motor is adopted as a driving mechanism, a common base, maintenance and centering are not needed, a bearing box of the pump is not needed either, the overall structure can be greatly simplified, and the occupied area is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of fluid equipment, and particularly to a centrifugal pump. Background Art

[0002] Currently, most of the motors supporting centrifugal pumps adopt radial flux motors. As Figure 1 shown, a flexible coupling 14 (the coupling 14 is covered by a coupling protective cover 13) is used to connect between the motor 12 and the pump shaft. The pump 15 adopts a structure supported by double-ended bearings and needs to be equipped with a shaft seal to isolate the bearing housing from the pump body, and then the impeller, shaft seal and bearing housing are strung together by the pump shaft. For the convenience of on-site installation of the pump, generally the pump and the motor are integrally installed on a common base 11, and the alignment of the pump and the motor is adjusted before leaving the factory.

[0003] This traditional structure has the following disadvantages: a flexible coupling is required to connect the motor and the pump, and a common base needs to be added to install the pump and the motor. During the operation and maintenance process, the alignment needs to be regularly checked to ensure the stable operation of the pump set; the overall size and weight are very large, especially only the outermost ring part of the coil of the radial flux motor participates in the work process; in order to adapt to the on-site pipeline layout, clockwise and counterclockwise configurations need to be designed; the pump shaft needs to be designed according to the maximum torque of the pump; when a variable-frequency motor is equipped, no matter what speed the motor runs at, the iron loss of the motor remains basically unchanged. Summary of the Invention

[0004] In order to solve the above technical problems, the object of the present invention is to provide a centrifugal pump with a simple structure and a small floor area.

[0005] The technical solution provided by the present invention is as follows: A centrifugal pump includes a pump body, a pump shaft, a sealing mechanism, an impeller, and an axial flux motor; the pump shaft is rotatably installed on the pump body through the sealing mechanism to form a sealed cavity inside the pump body; the impeller is installed on the pump shaft and is located in the sealed cavity, and at least one end of the pump shaft is installed with an axial flux motor, and the axial flux motor drives the impeller to rotate through the pump shaft to realize the transportation of fluid.

[0006] Preferably, axial flux motors are installed at both ends of the pump shaft.

[0007] Preferably, the centrifugal pump is a double-suction pump.

[0008] Preferably, the axial flux motor includes a bearing seat, a bearing gland, and a driving rotor. The driving rotor is installed on the pump shaft, and a plurality of permanent magnets are uniformly arranged. The bearing gland is installed outside the bearing seat to form a cavity surrounding the driving rotor, and the bearing gland and the bearing seat are both uniformly provided with first winding blocks and second winding blocks having the same number as the permanent magnets.

[0009] Preferably, the bearing housing is provided with a first cooling water chamber, and the first cooling water chamber is sealed by a first water seal plate; the bearing gland is provided with a second cooling water chamber, and the second cooling water chamber is sealed by a second water seal plate; a cooling water coil is further provided between the bearing housing and the driving rotor.

[0010] Preferably, a plurality of first protrusions extend outward from the outer surface of the inner end wall of the bearing housing, the outer surfaces of the first protrusions are respectively matched with corresponding first winding blocks, and the inner surface is provided with a first concave portion as a part of the first cooling water chamber; a plurality of second protrusions extend inward from the inner surface of the bearing gland, the outer surfaces of the second protrusions are respectively matched with corresponding second winding blocks, and the inner surface is provided with a second concave portion as a part of the second cooling water chamber.

[0011] Preferably, the sealing mechanism includes a mechanical seal dynamic ring, a mechanical seal static ring, packing gland, and packing gland cover; the mechanical seal dynamic ring is fixed on the pump shaft, the mechanical seal static ring is fixed on the pump body, and the mechanical seal dynamic ring and the mechanical seal static ring seal the sealing cavity; a receiving groove for accommodating the packing gland is provided at the outer end of the mechanical seal static ring, and the packing gland cover can be installed at the end of the receiving groove and press the packing gland, so that when the mechanical seal between the mechanical seal dynamic ring and the mechanical seal static ring fails, the packing gland and the packing gland cover can be installed on the mechanical seal static ring to achieve packing seal.

[0012] Preferably, an exhaust mechanism is further included, and the exhaust mechanism includes an automatic exhaust valve, and the automatic exhaust valve communicates the high-pressure area of the pump body sealing cavity with two low-pressure areas.

[0013] Preferably, the exhaust mechanism includes a first four-way pipe, which is respectively connected to the automatic exhaust valve, the exhaust hole of the high-pressure area of the sealing cavity, and the first pipelines respectively connected to the exhaust holes of the two low-pressure areas of the sealing cavity. Check valves are provided on the first pipelines respectively connected to the exhaust holes of the two low-pressure areas of the sealing cavity.

[0014] Preferably, a leakage prevention mechanism is provided between the pump body and the impeller, and the leakage prevention mechanism includes a sealing ring. The sealing ring is provided with two threaded holes below its center line, and two screws are respectively installed in the threaded holes from the outside to the inside. The pump body is provided with positioning grooves at the positions corresponding to the screw heads, and the cooperation between the screw heads and the positioning grooves is used to limit the rotation of the sealing ring with the impeller and prevent the screws from coming out of the threaded holes.

[0015] Compared with the prior art, the centrifugal pump of the present invention uses an axial flux motor as the driving mechanism, does not require a common base, does not require maintenance alignment, and does not require the bearing box of the pump itself, which can greatly simplify the overall structure and reduce the floor area. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments described in the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic structural diagram of an existing centrifugal pump; Figure 2 It is a schematic structural diagram of the centrifugal pump according to the embodiment of the present invention; Figure 3 It is Figure 2 A schematic diagram of the axial flux motor in the centrifugal pump shown; Figure 4 It is Figure 3 A cross-sectional view along line C-C; Figure 5 It is Figure 3 A schematic diagram of the drive rotor and the permanent magnet in the axial flux motor shown; Figure 6 It is Figure 3 A perspective view of the bearing end cover in the axial flux motor shown; Figure 7 It is Figure 6 A perspective view of the bearing end cover from another angle shown; Figure 8 It is Figure 2 A schematic diagram of the sealing mechanism in the centrifugal pump shown; Figure 9 It is Figure 2 A schematic diagram of the exhaust mechanism in the centrifugal pump shown; Figure 10 It is Figure 2 A partial enlarged view of the anti-leakage mechanism, the pump body and the impeller in the centrifugal pump shown; Figure 11 It is Figure 10 A side view of the anti-leakage mechanism shown. Detailed implementation manners

[0018] In order to enable those skilled in the art to better understand the technical solutions in the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present application.

[0019] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly disposed on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0020] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0021] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality of" and "several" is two or more, unless otherwise specifically defined.

[0022] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the implementation conditions of the present application. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change of the ratio relationship, or adjustment of the size, without affecting the efficacy and the purpose that the present application can achieve, should still fall within the scope covered by the technical content disclosed in the present application.

[0023] As Figures 2 to 11 shown, an embodiment of the present invention provides a centrifugal pump, specifically a double-suction pump. In other embodiments, it can also be other centrifugal pumps other than double-suction pumps.

[0024] The centrifugal pump includes a pump body 2, a pump shaft 3, a sealing mechanism 4, an impeller 5, an axial-flux motor 6, and an exhaust mechanism 7. The pump shaft 3 is rotatably installed on the pump body 2 through the sealing mechanism 4 to form a sealed cavity inside the pump body 2. The impeller 5 is installed on the pump shaft 3 and is located in the sealed cavity. Axial-flux motors 6 are installed at both ends of the pump shaft 3 to form a double-drive mechanism (in other embodiments, the axial-flux motor 6 can also be installed only at one end of the pump shaft 3). The impeller 5 is driven to rotate by the axial-flux motor 6 through the pump shaft 3 to achieve fluid transportation. Using an axial-flux motor as the drive mechanism does not require a common base, does not require maintenance alignment, and does not require the bearing box of the pump itself, which can greatly simplify the overall structure and reduce the floor area.

[0025] Compared with the traditional structure, the double-drive double-suction pump adopting the axial-flux motor 6 in this embodiment has the following advantages: The axial-flux motor 6 is directly used to replace the bearing box of the double-suction pump and is installed at both ends of the double-suction pump. There is no need for a common base, no need for maintenance alignment, and no need for the bearing box of the pump itself, which greatly reduces the full life cycle cost of the product; The axial-flux motor 6 has no cooling fan, and the noise of the unit is smaller. The double-suction pump structure of the present invention is of a coaxial form, with better concentricity and less vibration of the product; The magnetic fields generated by the coils of the axial-flux motor 6 from the inside to the outside can all participate in the work process. Therefore, the power density of the axial-flux motor is much larger than that of the radial-flux motor, and the efficiency is also higher. After reducing components such as the common base, coupling, motor coil, and motor heat dissipation in this embodiment, the weight and floor area are both reduced by more than 50% compared with the double-suction pump unit of the traditional structure, and the construction cost of the pump house also decreases accordingly; Adopting double-drive with axial-flux motors at both ends, the same structure is used for both clockwise and counterclockwise directions, with better adaptability and correspondingly less inventory of parts for the manufacturer; Adopting double-drive with axial-flux motors at both ends, torque is input simultaneously on both sides. The pump shaft 3 can be designed with a shaft diameter according to half of the maximum torque of the pump, the material of the shaft can be reduced, and after the shaft is reduced, the inlet area of the pump impeller 5 is correspondingly increased, improving the cavitation performance of the pump; Adopting double-drive with axial-flux motors, when the speed of the pump drops below 75%, only one side of the motor can be operated to meet the power requirements of the unit operation, and the energy consumption of the unit is lower.

[0026] In summary, the centrifugal pump in this embodiment has the characteristics of high operating efficiency, small floor area, and convenient installation, and is more suitable for prefabricated pump houses, water supply in residential living areas and other fields compared with the double-suction pump of the traditional structure.

[0027] As Figure 3 、 Figure 4 shown, in this embodiment, the two axial-flux motors 6 have the same structure and are arranged in a mirror image at both ends of the pump shaft 3. Each axial-flux motor 6 includes a bearing seat 61, a bearing gland 62, and a drive rotor 63. The drive rotor 63 is installed on the pump shaft 3, and a plurality of permanent magnets 64 are evenly arranged (as Figure 5As shown, there are 12 in this embodiment, which are installed in the through holes evenly arranged on the driving rotor). The bearing gland 62 is installed on the outside of the bearing housing 61 to form a cavity surrounding the driving rotor 63. The bearing gland 62 and the bearing housing 61 are both evenly provided with the same number of first winding blocks (not shown) and second winding blocks 69 as the permanent magnet 64 (the windings of the first winding block and the second winding block extend out to connect the axial flux motor 6 to the power supply). The axial flux motor 6 is formed by the cooperation of the permanent magnet 64 with the first winding block and the second winding block. Inside the bearing housing 61, there is also a bearing 66 and a bearing end cover 67. A locking nut 68 is also installed at the end of the pump shaft.

[0028] Adopting this bearing body component with a driving function can reduce the coupling component and reduce the running vibration; it can eliminate the need for an additional motor, reduce the floor area of the unit, and is suitable for occasions with requirements for equipment size such as on ships and offshore platforms; it is more suitable for the environment powered by power batteries and is convenient for use in areas without grid power supply such as various emergency and mobile facilities.

[0029] Combined Figure 6 、 Figure 7 As shown, in this embodiment, the bearing gland 62 is provided with a second cooling water cavity 621, and the second cooling water cavity 621 is sealed by a second water seal plate 622. The second cooling water cavity 621 realizes water inlet and drainage through a second cooling water cavity interface 623. The inner surface of the bearing gland 62 extends inward to form a plurality of second protrusions 624. The outer surfaces of the respective second protrusions 624 are respectively matched with the corresponding second winding blocks, and the inner surface is provided with a second concave portion 625 as a part of the second cooling water cavity 621. The bearing housing 61 is provided with a first cooling water cavity 611, and the first cooling water cavity 611 is sealed by a first water seal plate 612. The first cooling water cavity 611 realizes water inlet and drainage through a first cooling water cavity interface 613. The outer surface of the inner end wall of the bearing housing 61 extends outward to form a plurality of first protrusions 614. The outer surfaces of the respective first protrusions 614 are respectively matched with the corresponding first winding blocks, and the inner surface is provided with a first concave portion as a part of the first cooling water cavity 611 (the shape and structure of the first protrusion 614 and the first concave portion are respectively similar to those of the second protrusion 624 and the second concave portion 625). A cooling water coil 65 is also provided between the bearing housing 61 and the driving rotor 63, which is glued to the inner wall of the bearing housing 61 with heat-conducting glue, and realizes water inlet and drainage through a cooling water coil interface 651. The above-mentioned first cooling water cavity interface 613, second cooling water cavity interface 623, and cooling water coil interface 651 are all connected to the inside of the pump body 2 through a third pipeline, and the cooling water source is provided by the pump itself. Through the above structure, the bearing body component adopts a multi-region water-cooling layout, which can effectively reduce the influence brought by the winding heat generation.

[0030] As Figure 8As shown in the figure, in this embodiment, the sealing mechanism 4 includes a mechanical seal dynamic ring 41, a mechanical seal static ring 42, a packing gland 43, and a packing gland 44 (a split packing gland is adopted in this embodiment). The mechanical seal dynamic ring 41 is fixed on the pump shaft 3, and the mechanical seal static ring 42 is fixed on the pump body 2. The mechanical seal dynamic ring 41 and the mechanical seal static ring 42 seal the sealing cavity. An accommodation groove for accommodating the packing gland 43 is provided at the outer end of the mechanical seal static ring 42. The packing gland 44 can be installed at the end of the accommodation groove and press the packing gland 43, so that when the mechanical seal between the mechanical seal dynamic ring 41 and the mechanical seal static ring 42 fails, the packing gland 43 and the packing gland 44 can be installed on the mechanical seal static ring 42 to achieve packing seal.

[0031] This solution can solve the problem that the original mechanical seal structure must be repaired immediately when it is damaged. It does not need to be repaired immediately, can meet the emergency use requirements, and can notify the professional personnel of the equipment manufacturer to replace the mechanical seal while in use. Moreover, the capital occupation brought by the packing gland and the split packing gland is less than that of the spare mechanical seal, and the operation difficulty of installing the packing and the split packing gland is smaller. This solution can also be used in special occasions such as emergency water supply and marine pumps.

[0032] As Figure 9 shown in the figure, in this embodiment, the exhaust mechanism 7 includes an automatic exhaust valve 71. The automatic exhaust valve 71 communicates the high-pressure area (high-pressure water outlet area) A of the sealing cavity of the pump body 2 with two low-pressure areas (low-pressure water inlet areas) B. Specifically, the exhaust mechanism further includes a first four-way pipe 72, which is respectively connected to the automatic exhaust valve 71, the exhaust hole of the high-pressure area of the sealing cavity, and a first pipeline 73 respectively connected to the exhaust holes of the two low-pressure areas of the sealing cavity. A check valve 74 is provided on the first pipeline 73 respectively connected to the exhaust holes of the two low-pressure areas of the sealing cavity. This solution can solve the problems that the original automatic exhaust valve only exhausts the accumulated gas in the high-pressure area, the exhaust holes in the low-pressure area are blocked by a plug, it is inconvenient to unscrew the exhaust with a wrench during installation and commissioning, and the liquid in the pump will also be discharged and pollute the equipment surface, etc., and achieve the purpose of conveniently exhausting the accumulated gas in the pump. Moreover, by setting the check valve, the liquid in the high-pressure area is effectively prevented from flowing back to the low-pressure area. A second four-way pipe 75 is also provided between the first four-way pipe 72 and the exhaust hole of the high-pressure area of the sealing cavity. The second four-way pipe 75 is respectively connected to the mechanical seal through two second pipelines 76, and is used to spray water between the mechanical seal dynamic ring 41 and the mechanical seal static ring 42, so as to play a role in lubricating, flushing and cooling the mechanical seal.

[0033] As Figure 10 、 Figure 11As shown, in this embodiment, a leakage prevention mechanism is provided between the pump body 2 and the impeller 5 to reduce leakage from the high-pressure water outlet area to the low-pressure water inlet area during the operation of the pump. The leakage prevention mechanism includes a sealing ring 8. The sealing ring 8 is provided with two threaded holes below its center line. Two screws 9 (in this embodiment, they are socket head cap screws with a Teflon coating on the surface) are respectively installed in the threaded holes from the outside to the inside. The pump body 2 is provided with positioning grooves 21 at the positions corresponding to the heads of the screws 9. The cooperation between the heads of the screws 9 and the positioning grooves 21 is used to restrict the rotation of the sealing ring 8 with the impeller 5 and prevent the screws 21 from coming out of the threaded holes. At the same time, during the operation of the pump, the rotation of the impeller 5 will cause high-pressure and low-pressure areas to be formed in the sealing cavity. The pressure difference between the high-pressure and low-pressure areas presses the sealing ring 8 tightly against the pump body, which restricts the axial movement of the sealing ring 8. Compared with the existing friction force formed by the elastic deformation of the elastic cylindrical pin, the screw thread is less likely to come out; the existing elastic cylindrical pin has a hollow structure, and drilling through the positioning hole on the sealing ring is likely to cause additional leakage. In the case of a thin-walled sealing ring, the threaded hole has better sealing performance; the existing elastic cylindrical pin requires an elastic material to be used and is limited in use in corrosive media, while most materials can be processed into socket head cap screws (when in normal use, a 316L substrate can be used, which is applicable to most media); the socket head cap screws are coated with Teflon to increase corrosion resistance and insulation, which can effectively reduce the influence of electrochemical corrosion on the screws and reduce the risk of screw fracture.

[0034] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A centrifugal pump, characterized in that: It includes a pump body, a pump shaft, a sealing mechanism, an impeller, and an axial flux motor; the pump shaft is rotatably mounted on the pump body through the sealing mechanism, and a sealed cavity is formed inside the pump body; the impeller is mounted on the pump shaft and is located in the sealed cavity, and an axial flux motor is mounted on at least one end of the pump shaft, and the impeller is driven to rotate through the pump shaft by the axial flux motor to realize fluid transportation.

2. The centrifugal pump according to claim 1, characterized in that Axial flux motors are installed at both ends of the pump shaft.

3. The centrifugal pump according to claim 1, characterized in that The centrifugal pump is a double-suction pump.

4. The centrifugal pump according to claim 1, characterized in that The axial flux motor includes a bearing seat, a bearing cover, and a driving rotor. The driving rotor is installed on a pump shaft and has multiple permanent magnets evenly arranged. The bearing cover is installed on the outside of the bearing seat to form a cavity surrounding the driving rotor. The bearing cover and the bearing seat are evenly provided with the same number of first winding blocks and second winding blocks as the permanent magnets.

5. The centrifugal pump according to claim 4, characterized in that The bearing seat is provided with a first cooling water chamber, which is sealed by a first water seal plate; the bearing pressure cover is provided with a second cooling water chamber, which is sealed by a second water seal plate; a cooling water coil is also provided between the bearing seat and the driving rotor.

6. The centrifugal pump according to claim 5, characterized in that The outer surface of the inner end wall of the bearing seat is provided with a plurality of first protrusions extending outward, the outer surface of each of the first protrusions is respectively matched with the corresponding first winding block, and the inner surface is provided with a first inner recess as a part of the first cooling water chamber; the inner surface of the bearing pressure cover is provided with a plurality of second protrusions extending inward, the outer surface of each of the second protrusions is respectively matched with the corresponding second winding block, and the inner surface is provided with a second inner recess as a part of the second cooling water chamber.

7. The centrifugal pump according to claim 1, characterized in that The sealing mechanism comprises a mechanical seal dynamic ring, a mechanical seal static ring, a packing and a packing gland; the mechanical seal dynamic ring is fixed on the pump shaft, the mechanical seal static ring is fixed on the pump body, and the mechanical seal dynamic ring and the mechanical seal static ring seal the sealing cavity; the outer end of the mechanical seal static ring is provided with a receiving groove for receiving the packing, and the packing gland can be installed at the end of the receiving groove and press the packing, so that when the mechanical seal between the mechanical seal dynamic ring and the mechanical seal static ring fails, the packing packing and the packing gland can be installed on the mechanical seal static ring to realize the packing seal.

8. The centrifugal pump according to claim 1, characterized in that It also includes an exhaust mechanism, which includes an automatic exhaust valve, and the automatic exhaust valve connects the high-pressure area and two low-pressure areas of the pump body sealing cavity.

9. The centrifugal pump according to claim 8, characterized in that The exhaust mechanism includes a first four-way pipe, which is respectively connected to the automatic exhaust valve, the high-pressure area exhaust hole of the sealed cavity, and the first pipeline respectively connected to the two low-pressure area exhaust holes of the sealed cavity. A check valve is provided on the first pipeline respectively connected to the two low-pressure area exhaust holes of the sealed cavity.

10. The centrifugal pump according to claim 1, characterized in that An anti-leakage mechanism is provided between the pump body and the impeller, and the anti-leakage mechanism includes a sealing ring. The sealing ring is provided with two threaded holes below its center line, and two screws are respectively installed in the threaded holes from the outside to the inside. The pump body is provided with a positioning groove at the position corresponding to the screw head. The screw head cooperates with the positioning groove to limit the sealing ring from rotating with the impeller and prevent the screw from falling out of the threaded hole.

Images